Diaphragm gauge



P. GAISER DIAPHRAGM GAUGE Filed sept. 24, 1951 Nov. 24,1936.

infested Nev. 24,1936

4UlSuTED STATES PATENT FFICE DIAPHRAGM GAUGE Application September 24, 1931, Serial No.564-,943 10 claims. (ci. '1s-11o).

The present invention relates to low pressure diaphragm gauges. A

More speciflcally, the invention relates to pressuregauges for `use in connection with automobiles for indicating the depth of gasoline in the tank; the depth of the water in the radiator,` the depth of the oil in the crankcase, or the pressure existing in the pressure oil system, for example.

Diaphragm gaugesv of numerous varied designs have heretofore been constructed, in `which a flexible metallic diaphragm, upon pressure-responsive movement thereof, imparted movement to a pointer or similar indicating means movable along ascale on the gauge dial.

vertently subjected to excessive pressures or uctuations in pressure, and it has been found that the diaphragms lof the gauges now in use are frequently ruptured as a result'. Moreover, these gauges are sometimes subjected to pressures be- 20. low atmospheric pressure with the result that the diaphragms have been distorted rearwardly with damage thereto. These abnormal fluctuationsalso may lcause bending of the pointer or l its actuating members with the result that the pointer will not return to zero. The fact that y the pointer actuating members have been bent or distorted-'destroys the accuracy of the gauge even though the pointer may be restored to zero by adjustment.

ln some types of vgauges now onthe market,

the journals-for the various pointer actuating members are formedwithout suiiicient strength .or accuracy, as by stamping out of sheet metal. Such construction is found-in practice to be unsatisfactory in that these various members are not givensumcient support. Accordingly the pointer actuating members are allowed too much fredomin their movements and the accuracy oi' the gauge is` aiiected inasmuch as the 40 pointer may give a certain reading under a given pressure inoneinstance and give a dierent reading at another' time, the pressure. in fact' being the same as inthe first instance.

Another disadvantage vfound in some oi' the v4.5 gauges on the market today is thatthey `are so from the'position it should assume, with the In practice these gauges are frequently inaddiaphragms of very light material may be used. These springs are usually inserted inthe diaphragm case and bear against the diaphragm. The great drawback to this construction is Kthat the springs are diliicult of access, for adjustment 5 and replacement.

It has furtherbeen found that in assembling gauges of this nature, the mechanism assembly is sometimes placed in the gauge casing in such a position that the dial is angularly displaced10 result that the gauge cannot properly read, and must be disassembled in order to correct the position of the mechanism assembly with respect to the casing.

Accordingly it is an object of this invention l to provide a gauge which will accurately indicate pressures under all sorts of adverseconditions, such as excessive pressures, and will withstand violent fluctuations in pressures without damage v to its mechanism or in any way affecting the 20 accuracy thereof.

Another object of the present invention is to provide a gauge that is so constructed that the movement of the diaphragm is definitely 'limited in both directions so that it will not be ruptured 25 when subjected to excessive pressures or pressures below atmospheric.

l It is also an object todevise an improved movement mechanism.

A further object of this invention is to pro- 30 v `existed in the pointer actuating members.

Another object of this invention is to provide 4o a gauge that may be readily disassembled in the event that it becomes necessary to repair or ad- Just elements of the mechanism.

A still further object of this invention is to produce a gauge wherein yielding means are provided to resist the movements oi' the diaphragm in response to iiuid pressure. The yielding means compels the diaphragm to take a smooth regular motion, thereby greatly assisting in obtaining an even scale calibration and assuring an instant return of the diaphragm to its normal position. This .yielding means 'is of especially great value in a low pressure gaugein that, by its offering substantial yresistance to the pressure responsive movement of the diaphragm. a diaphragm con-l structed of a very thin or soft material may be used. The advantages of an unusually soft or thin diaphragm are that it has extreme sensitivity and accuracy due to its low and uniform inherent resistance to movement. The dia phragms of gauges in the past have been constructed of such a material and in such a manner that they were quite rigid and offered substantial and non-uniform resistance to movement, and this resistance, unless compensated for, entered into the scale readings with the result that the readings did not give a true indication of the pressure-throughout the entire scale range. The yielding means resisting the diaphragm movement preferably comprises a metal arm of such a nature and associated with the diaphragm in such a manner that it may be removed from the gauge without disturbing the diaphragm or any of the other related gauge parts.

Another object of this invention is to provide a gauge having a means carried thereby to eiliciently sec`ure it to the dash of an automobile or other supporting surface, so that the gauge may be quickly mounted thereon or removed therefrom, yet when in place is rigidly secured.

A still further object of the present invention is to provide a gauge wherein the gauge casing and mechanism assembly have interengaging parts of such a nature that, as the mechanism assembly is placed in the casing, their 'correct angular relationship is assured.

With these objects in view, as well as others that will become apparent from the following disclosure, reference will bephad to the accompanying drawing forming part of the same and in which:

Figure 1 is a front view of my improved gauge with certain parts cut away in order to illustrate the mechanism in the casing.

Figure 2 is an elevation partly in section of the gauge and the attaching means, and

Figure 3 is a detail view, partly in section, of the means for assuring the correct positioning of the mechanism in the casing.

Referring to the drawing, in which like characters designate like parts, I designates the gauge casing which preferably is of cylindrical formation, and is provided with an outturned flange II at the front'open end thereof. The open end of this casing is closed by a unitary crystal assembly comprising a sleeve I2 so formed i as to have a flange I3 which abuts. the fiange II on the casing', and a ange I4 against which a crystal I5 is pressed by flanged ring I5 that is frictionally fitted within the sleeve I2.

The casing I0 is apertured in the rear at I1 to receive a shoulder I8 on a cast or forged base or block I9. This base block I9 supports the entire mechanism of the gauge, including the dial and pointer, and is provided with a reduced threaded terminal 2|, upon which is screwed a nut 22 with which to draw the face 23 of the casting up against the inner wall of the casing I0, so as to flrmly secure the same inthe assembled relationship. This terminal has an axial fluid passage 20, and is adapted to receive a pressure pipe (not shown).

The face of the base block- I9 is provided with Aan annular recess 24 which, with a diaphragm 25,

forms a pressure chamber 26. The diaphragm seats on a' shoulder 21 formed on the block, and has a flanged periphery 28 which rests against a wall 29 formed in the block. A diaphragm plate in this relationship by means of solder or the like as at 33. The diaphragm preferably is made either of an extremely thin or unusually soft metal so as to offer very little resistance to fluid pressure, so that a very slight pressure, such as caused by a low head of water or oil will produce a deflection of the same. The diaphragm is thus seen to be very sensitive, and by virtue thereof, through the medium of the pointer mechanism, the -gauge accurately indicates very low fluid pressures.

For protection of the diaphragm against abnormal pressure conditions, the deflection of the diaphragm is limited in one direction by the diaphragm plate 3|, which has circular corrugations 34 therein to correspond to the circular corrugations 35 formed in the diaphragm; and the deflection of the diaphragm in the other direction (that is, to the right in Figure 2) is limited by means of a stop member 36 formed on the block in the pressure chamber. This arrangement permits an extremely soft or light diaphragm of great sensitivity to be used. To prevent the diaphragm from sealing oi the pressure chamber from the pressure source transverse by-pass slots 31 are formed in the stop member 36.

4Standards 38 extend from the front face of the base block and have shouldered pins 39 and 40 frictionally fitted in the extremities thereof. Pivoted at each of its ends on these pins -is a yoke member 4I, at the mid-portion of which is provided, as by striking a piece out of the metal. a finger or crank 42, which bears against the face of an actuator or plug 43. The plug 43 extends through the central aperture in the diaphragm plate 3|, and is secured, as by soldering to the diaphragm 25.

One end of the yoke member has a. lever 44 formed thereon. This lever slidably bears against a pointer 45 to cause the same to pivot and sweep over the scale in one direction to indicate the pressure to which the gauge is subjected. The pointer 45 is plvoted on a headed pin 46 which is set into the base block at 41. The scale above referred to is a dial 48 which is formed on'a. scale plate 49.

'I'he pointer, along with the yoke member, is returned to zero position by means of a coil spring 5I which encircles pin 40. One end 52 vof the spring bears against the block I9, and its other extremity 53 extends through an aperture 54 formed in the pointer.

The scale plate issecured to the base block vby means of two pins 55 which have reduced end portions 56 which extend through and are frictionally held in openings 51 formed in the base block I9. The extremities of the reduced portions constitute the means above mentioned for prel venting an incorrect positioning of the mechanism assembly relative to the casing. The scale plate held on the other end of the pins by means of headed screws 59 passing through openings in the dial and threaded yinto the ends of the pins. The diaphragm motion-regulating means comprises a spring arm 60 which may be formed of any suitable metal or alloy. One end of this spring arm is secured to the base block by means of a screw 6I. The other end of this member is forked to provide two ngers 62 which freely embrace the reduced portion 63 of the plug 43 eww `result in an even scale calibration.

resisting spring which 'takes-the load `of forces set up by iluid' pressure, 'allows .a diaphragm constructed of very lighti gauge or'soft material to be used which, by virtue of'its lightness offers but little resistance to deflection and thus is very sensitive to iiuid pressures. l

The means which I have provided for securing the gauge to the support comprises aU-shaped member 65 having legs 66. These legs are adaptved to clamp, between them and the ange Il on the casing I0, the automobile dash shown at 61.

vMeans are provided for drawing the gaugel casing and the U-shaped member together. comwith an aperture slightly largerthan .the cylindrical portion of the gauge casing I0. The gauge is then inserted in the opening and flange Il is caused to abut the face of the dash. 'I'he U- shaped bracket member isthen applied over the bolts 68, and the nuts 13 are turned on the bolts and taken up, thus drawing the casing back into the dash opening and .l'mly clamping the ilange lIl against the tace of the dash.

In order that the gauge casing may be accurately located with respect to the dash opening, a relatively large opening Il is formed' in the bracket 65, it being seen from this construction that the projection 2| passing through this opening will be allowed considerable free play therein for purposes of adjustment.V

It will be seen from the foregoing that'ina gauge constructed as above described, by removing the crystal assembly and unscrewing the nut 22 the entire gauge mechanism may be removed by drawing the same forwardly out ofthe gauge casing.

It also will'be seen that the diaphragm, when moving to the right as shown in Figure 2 to its limit, will contact the stop 38 only in the region of the plug 43, forming a seat for the same whereby distortion of the very light or soft ,diaphragm is prevented. l

lIhe invention may be embodied in other Specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention beingV indicated by the appended claims rather than by the foregoing description, and all changes Vwhich come within said studs being located on said rear face and projecting therebeyond; the rear wall of the casing being provided with apertures through which the said studs extend; land means for rmly clamping and holding the rear face of said base in contact with' the rear wall of the casing;

whereby, in assembling the parts, said studs cooperating with said apertures will definitely locate said base with respect to said casing.

2. In a gauge, a casing having a rear wall containing a large opening and small openings; a mechanism supporting base 4having a rear face;

studs located in said rear face and extending through said small openings in said rear wall and means for iirmly clamping and holding the rear face of said base in contact with the rearwall of the casing, said means comprising an integral threaded extension of the base projected through said large opening in the rear wall of the casing, and a nut turned thereon; whereby, in assembling the parts, said studs and small openings will detlnitely position said base with respect to said casing.

3. In `a gauge, a casing; a base and means for detachably securing the same in said casing; said base having a rear face and a front face, the front face having a recess therein; a diaphragm having annular corrugations provided therein, and a diaphragm plate having annular corrugaf tions corresponding with the corrugations in said diaphragm and positioned in said recess in superposed relationship, the bottom of the recess and the diaphragm denng a pressure chamber; and asealing material located about the margin of `the said plate and filling the space between the side wall of the recess, the'edge ofthe 'diaphragm and the plate.

4. In a gauge, a casing having an opening in the rear wall thereof; a base. having front and rear faces; the rear face of the same having an integral boss projecting through said opening in the rear wall of thecasing; the front face of the base having a recess therein and-a central boss -plate having corrugations corresponding to the 4corrugations in the diaphragm mounted thereover, whereby excessive forward iiexing of the diaphragm is prevented and means securing the base in the casing.

5'. In a gauge, a casing;` a pressure chamber and a diaphragm cooperating therewith, the diaphragm having annular corrugations therein; a'

stop plate provided with corrugations correspond- Ving to the corrugations o f said diaphragm mounted thereover, said stop platel having a central hole formed therein, a shouldered plug mounted on said diaphragm and projecting through said centrai hole, acompensating spring located within the casing and bearing against said shouldered plug to oppose movement of said diaphragm in response to fluid pressure whereby the diaphragm may be made of much softer or lighter material than would be possible if said spring were absent.

6. In a gauge, a diaphragm; a shouldered acltuator mounted on said diaphragm; a vspring member having one end terminating in avfork deiining two lingers. said fingers being adapted to contact and bear against said. shouldered actu- Cil relation to said actuator.

7. In a gauge, a base block having a diaphragm, said block having two standards projecting from its face; and a yoke member pivoted at each end on a pin provided on each standard, said yoke member being provided at its mid-section with a bendable crank for adjustable cooperation with the diaphragm.

8. In a gauge, a base block having a diaphragm and a pointer associated therewith, said block having two standards projecting from a face thereof; and a yoke member pivoted at its ends on said standards, said yoke member being provided at its midsection with a bendable crank for adjustable cooperation with the diaphragm, and at one end thereof with a lever arm for cooperation with the pointer.

9. In a gauge, a base block and a' pointer associated therewith; two standards projecting from said base block; a pin mounted in each of staid standards and being disposed substantially in axial alignment; a yoke member pivoted on said pins, a lever projecting from one end oi.' said yoke member and adapted to actuate said pointer; a torsion spring encircling one oi.' said pins,

fone end of said spring bearing against said base block and the other end thereof bearing against said pointer and adapted to return the same to zero position.

10. In a gauge, a casing having an opening, a base block having an aperture mounted in said casing, a scale plate mounted on said base block by means of a shouldered pin, the reduced end oi said pin extending through said aperture in said base block and projecting beyond said base block into said opening in said casing.

PAUL GAISER. 

